Send responses for any pending 'analysis.getErrors' requests during context removal.

pkg/analysis_server/test/mocks.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library mocks;
 
 import 'dart:async';
 import 'dart:io';
 
 @MirrorsUsed(targets: 'mocks', override: '*')
@@ skipping 137 matching lines @@
     // Wrap send notification in future to simulate websocket
     // TODO(scheglov) ask Dan why and decide what to do
 //    new Future(() => notificationController.add(notification));
     notificationController.add(notification);
   }
 
   /**
    * Simulate request/response pair.
    */
   Future<Response> sendRequest(Request request) {
-    var id = request.id;
     // Wrap send request in future to simulate websocket
     new Future(() => requestController.add(request));
-    pumpEventQueue().then((_) => responseController.addError(
-        new NoResponseException(request)));
-    return responseController.stream.firstWhere((response) => response.id == id
-        );
+    return waitForResponse(request);
   }
 
   @override
   void sendResponse(Response response) {
     responsesReceived.add(response);
     // Wrap send response in future to simulate websocket
     new Future(() => responseController.add(response));
   }
 
   void expectMsgCount({responseCount: 0, notificationCount: 0}) {
     expect(responsesReceived, hasLength(responseCount));
     expect(notificationsReceived, hasLength(notificationCount));
   }
+
+  Future<Response> waitForResponse(Request request) {
+    String id = request.id;
+    pumpEventQueue().then((_) {
+      responseController.addError(new NoResponseException(request));
+    });
+    return responseController.stream.firstWhere((response) {
+      return response.id == id;
+    });
+  }
 }
 
 /**
  * A mock [AnalysisContext] for testing [AnalysisServer].
  */
 class MockAnalysisContext extends Mock implements AnalysisContext {
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }
 
 /**
@@ skipping 132 matching lines @@
   /**
    * Dependency list that will be returned by the next call to [computePackageMap].
    */
   Set<String> dependencies = new Set<String>();
 
   @override
   PackageMapInfo computePackageMap(resource.Folder folder) {
     return new PackageMapInfo(packageMap, dependencies);
   }
 }